Package io.micrometer.context

Interface ContextSnapshot

public interface ContextSnapshot

Holds values extracted from ThreadLocal and other types of context and exposes methods to propagate those values.

Use ContextSnapshotFactory.builder() to configure a factory to work with snapshots.

Implementations are disallowed to store null values. If a ThreadLocal is not set, or it's value is null, there is no way of distinguishing one from the other. In such a case, the ContextSnapshot simply must not contain a capture for the particular ThreadLocal. Implementations should filter out any null values after reading into the storage also obtained by calling ContextAccessor.readValues(Object, Predicate, Map), and should likewise ignore null values from ContextAccessor.readValue(Object, Object).

Since:

1.0.0

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	ContextSnapshot.Scope	An object to use to reset ThreadLocal values at the end of a context scope.

Method Summary

Modifier and Type	Method	Description
static ContextSnapshot	captureAll(ContextRegistry registry, Object... contexts)	Deprecated. use ContextSnapshotFactory.captureAll(Object...) on a factory obtained via a ContextSnapshotFactory.builder() combined with ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).
static ContextSnapshot	captureAll(Object... contexts)	Deprecated. use ContextSnapshotFactory.captureAll(Object...) on a factory obtained via a ContextSnapshotFactory.builder().
static ContextSnapshot	captureAllUsing(Predicate<Object> keyPredicate, ContextRegistry registry, Object... contexts)	Deprecated. use ContextSnapshotFactory.captureAll(Object...) on a factory obtained via a ContextSnapshotFactory.builder() and configure ContextSnapshotFactory.Builder.captureKeyPredicate(Predicate) and ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).
static ContextSnapshot	captureFrom(Object context)	Deprecated. use ContextSnapshotFactory.captureFrom(Object...) on a factory obtained via a ContextSnapshotFactory.builder().
static ContextSnapshot	captureFrom(Object context, ContextRegistry registry)	Deprecated. use ContextSnapshotFactory.captureFrom(Object...) on a factory obtained via a ContextSnapshotFactory.builder() combined with ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).
static ContextSnapshot	captureFrom(Object context, Predicate<Object> keyPredicate, ContextRegistry registry)	Deprecated. use ContextSnapshotFactory.captureFrom(Object...) on a factory obtained via a ContextSnapshotFactory.builder() and configure ContextSnapshotFactory.Builder.captureKeyPredicate(Predicate) and ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).
static ContextSnapshot.Scope	setAllThreadLocalsFrom(Object sourceContext)	Deprecated. use ContextSnapshotFactory.setThreadLocalsFrom(Object, String...) with no keys on a factory obtained via a ContextSnapshotFactory.builder().
static ContextSnapshot.Scope	setAllThreadLocalsFrom(Object sourceContext, ContextRegistry contextRegistry)	Deprecated. use ContextSnapshotFactory.setThreadLocalsFrom(Object, String...) with no keys on a factory obtained via a ContextSnapshotFactory.builder() combined with ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).
ContextSnapshot.Scope	setThreadLocals()	Set ThreadLocal values from the snapshot.
ContextSnapshot.Scope	setThreadLocals(Predicate<Object> keyPredicate)	Variant of setThreadLocals() with a predicate to select context values by key.
static ContextSnapshot.Scope	setThreadLocalsFrom(Object sourceContext, ContextRegistry contextRegistry, String... keys)	Deprecated. use ContextSnapshotFactory.setThreadLocalsFrom(Object, String...) on a factory obtained via a ContextSnapshotFactory.builder() combined with ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).
static ContextSnapshot.Scope	setThreadLocalsFrom(Object sourceContext, String... keys)	Deprecated. use ContextSnapshotFactory.setThreadLocalsFrom(Object, String...) on a factory obtained via a ContextSnapshotFactory.builder().
<C> C	updateContext(C context)	Update the given context with all snapshot values.
<C> C	updateContext(C context, Predicate<Object> keyPredicate)	Variant of updateContext(Object) to update the given context with a subset of snapshot values.
default Runnable	wrap(Runnable runnable)	Return a new Runnable that sets ThreadLocal values from the snapshot around the invocation of the given Runnable.
default <T> Callable<T>	wrap(Callable<T> callable)	Return a new Callable that sets ThreadLocal values from the snapshot around the invocation of the given Callable.
default <T> Consumer<T>	wrap(Consumer<T> consumer)	Return a new Consumer that sets ThreadLocal values from the snapshot around the invocation of the given Consumer.
default Executor	wrapExecutor(Executor executor)	Return a new Executor that sets ThreadLocal values from the snapshot around the invocation of any executed, Runnable.

Method Details

updateContext

<C> C updateContext(C context)

Update the given context with all snapshot values.

Type Parameters:

C - the type of the target context

Parameters:

context - the context to write to

Returns:

a context, possibly a new instance, with the written values

updateContext

<C> C updateContext(C context,
 Predicate<Object> keyPredicate)

Variant of updateContext(Object) to update the given context with a subset of snapshot values.

Type Parameters:

C - the type of the target context

Parameters:

context - the context to write to

keyPredicate - predicate for context value keys

Returns:

a context, possibly a new instance, with the written values

setThreadLocals

ContextSnapshot.Scope setThreadLocals()

Set ThreadLocal values from the snapshot.

Returns:

an object that can be used to reset ThreadLocal values at the end of the context scope, either removing them or restoring their previous values, if any.

setThreadLocals

ContextSnapshot.Scope setThreadLocals(Predicate<Object> keyPredicate)

Variant of setThreadLocals() with a predicate to select context values by key.

Parameters:

keyPredicate - selects keys for use when setting ThreadLocal values

Returns:

an object that can be used to reset ThreadLocal values at the end of the context scope, either removing them or restoring their previous values, if any.

wrap

default Runnable wrap(Runnable runnable)

Return a new Runnable that sets ThreadLocal values from the snapshot around the invocation of the given Runnable.

Parameters:

runnable - the runnable to instrument

Returns:

wrapped instance

wrap

default <T> Callable<T> wrap(Callable<T> callable)

Return a new Callable that sets ThreadLocal values from the snapshot around the invocation of the given Callable.

Type Parameters:

T - the type of value produced by the Callable

Parameters:

callable - the callable to instrument

Returns:

wrapped instance

wrap

default <T> Consumer<T> wrap(Consumer<T> consumer)

Return a new Consumer that sets ThreadLocal values from the snapshot around the invocation of the given Consumer.

Type Parameters:

T - the type of value produced by the Callable

Parameters:

consumer - the callable to instrument

Returns:

wrapped instance

wrapExecutor

default Executor wrapExecutor(Executor executor)

Return a new Executor that sets ThreadLocal values from the snapshot around the invocation of any executed, Runnable.

Parameters:

executor - the executor to instrument

Returns:

wrapped instance

See Also:

• ContextExecutorService
• ContextScheduledExecutorService

captureAll

@Deprecated
static ContextSnapshot captureAll(Object... contexts)

Deprecated.

use ContextSnapshotFactory.captureAll(Object...) on a factory obtained via a ContextSnapshotFactory.builder().

Capture values from ThreadLocal and from other context objects using all accessors from the global ContextRegistry instance.

Parameters:

contexts - one more context objects to extract values from

Returns:

a snapshot with saved context values

captureAll

@Deprecated
static ContextSnapshot captureAll(ContextRegistry registry,
 Object... contexts)

Deprecated.

use ContextSnapshotFactory.captureAll(Object...) on a factory obtained via a ContextSnapshotFactory.builder() combined with ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).

Capture values from ThreadLocal and from other context objects using all accessors from the global ContextRegistry instance.

Parameters:

registry - the registry to use

contexts - one more context objects to extract values from

Returns:

a snapshot with saved context values

captureAllUsing

@Deprecated
static ContextSnapshot captureAllUsing(Predicate<Object> keyPredicate,
 ContextRegistry registry,
 Object... contexts)

Deprecated.

use ContextSnapshotFactory.captureAll(Object...) on a factory obtained via a ContextSnapshotFactory.builder() and configure ContextSnapshotFactory.Builder.captureKeyPredicate(Predicate) and ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).

Variant of captureAll(Object...) with a predicate to filter context keys and with a specific ContextRegistry instance.

Parameters:

keyPredicate - predicate for context value keys

registry - the registry with the accessors to use

contexts - one more context objects to extract values from

Returns:

a snapshot with saved context values

captureFrom

@Deprecated
static ContextSnapshot captureFrom(Object context)

Deprecated.

use ContextSnapshotFactory.captureFrom(Object...) on a factory obtained via a ContextSnapshotFactory.builder().

Create a ContextSnapshot by reading values from the given context object.

Parameters:

context - the context to read values from

Returns:

the created ContextSnapshot

captureFrom

@Deprecated
static ContextSnapshot captureFrom(Object context,
 ContextRegistry registry)

Deprecated.

use ContextSnapshotFactory.captureFrom(Object...) on a factory obtained via a ContextSnapshotFactory.builder() combined with ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).

Create a ContextSnapshot by reading values from the given context object.

Parameters:

context - the context to read values from

registry - the registry to use

Returns:

the created ContextSnapshot

captureFrom

@Deprecated
static ContextSnapshot captureFrom(Object context,
 Predicate<Object> keyPredicate,
 ContextRegistry registry)

Deprecated.

use ContextSnapshotFactory.captureFrom(Object...) on a factory obtained via a ContextSnapshotFactory.builder() and configure ContextSnapshotFactory.Builder.captureKeyPredicate(Predicate) and ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).

Create a ContextSnapshot by reading values from the given context object.

Parameters:

context - the context to read values from

keyPredicate - predicate for context value keys

registry - the registry to use

Returns:

the created ContextSnapshot

setAllThreadLocalsFrom

@Deprecated
static ContextSnapshot.Scope setAllThreadLocalsFrom(Object sourceContext)

Deprecated.

use ContextSnapshotFactory.setThreadLocalsFrom(Object, String...) with no keys on a factory obtained via a ContextSnapshotFactory.builder().

Variant of setThreadLocalsFrom(Object, String...) that sets all ThreadLocal values for which there is a value in the given source context.

Parameters:

sourceContext - the source context to read values from

Returns:

an object that can be used to reset ThreadLocal values at the end of the context scope, either removing them or restoring their previous values, if any.

setAllThreadLocalsFrom

@Deprecated
static ContextSnapshot.Scope setAllThreadLocalsFrom(Object sourceContext,
 ContextRegistry contextRegistry)

Deprecated.

use ContextSnapshotFactory.setThreadLocalsFrom(Object, String...) with no keys on a factory obtained via a ContextSnapshotFactory.builder() combined with ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).

Variant of setThreadLocalsFrom(Object, String...) that sets all ThreadLocal values for which there is a value in the given source context.

Parameters:

sourceContext - the source context to read values from

contextRegistry - the registry with the accessors to use

Returns:

an object that can be used to reset ThreadLocal values at the end of the context scope, either removing them or restoring their previous values, if any.

setThreadLocalsFrom

@Deprecated
static ContextSnapshot.Scope setThreadLocalsFrom(Object sourceContext,
 String... keys)

Deprecated.

use ContextSnapshotFactory.setThreadLocalsFrom(Object, String...) on a factory obtained via a ContextSnapshotFactory.builder().

Read the values specified by from the given source context, and if found, use them to set ThreadLocal values. Essentially, a shortcut that bypasses the need to create of ContextSnapshot first via captureAll(Object...), followed by setThreadLocals().

Parameters:

sourceContext - the source context to read values from

keys - the keys of the values to read (at least one key must be passed)

Returns:

an object that can be used to reset ThreadLocal values at the end of the context scope, either removing them or restoring their previous values, if any.

setThreadLocalsFrom

@Deprecated
static ContextSnapshot.Scope setThreadLocalsFrom(Object sourceContext,
 ContextRegistry contextRegistry,
 String... keys)

Deprecated.

use ContextSnapshotFactory.setThreadLocalsFrom(Object, String...) on a factory obtained via a ContextSnapshotFactory.builder() combined with ContextSnapshotFactory.Builder.contextRegistry(ContextRegistry).

Variant of setThreadLocalsFrom(Object, String...) with a specific ContextRegistry instead of the global instance.

Parameters:

sourceContext - the source context to read values from

contextRegistry - the registry with the accessors to use

keys - the keys of the values to read (at least one key must be passed)

Returns:

an object that can be used to reset ThreadLocal values at the end of the context scope, either removing them or restoring their previous values, if any.